Hexagonal LaLuO3 as high-<i>κ</i> dielectric

Schäfer, A.; Mantl, S.; Hardtdegen, H.; Mikulics, Martin; Schubert, J.; Luysberg, M.; Besmehn, Astrid; Niu, Gang; Schroeder, Thomas

doi:10.1116/1.4904401

Cited by 6 publications

(15 citation statements)

References 18 publications

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“…It is interesting to note that the hexagonal GaN structure can be used to epitaxially stabilize non‐equilibrium oxide phases at room temperature, such as hexagonal LaLuO 3 and monoclinic Y 2 O 3 (Table ).…”

Section: Growth Physical and Electronic Structurementioning

confidence: 99%

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Kumah

Ngai

Kornblum

2019

Adv Funct Materials

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Functional oxides are an untapped resource for futuristic devices and functionalities. These functionalities can range from high temperature superconductivity to multiferroicity and novel catalytic schemes. The most prominent route for transforming these ideas from a single device in the lab to practical technologies is by integration with semiconductors. Moreover, coupling oxides with semiconductors can herald new and unexpected functionalities that exist in neither of the individual materials. Therefore, oxide epitaxy on semiconductors provides a materials platform for novel device technologies. As oxides and semiconductors exhibit properties that are complementary to one another, epitaxial heterostructures comprised of the two are uniquely poised to deliver rich functionalities. This review discusses recent advancements in the growth of epitaxial oxides on semiconductors, and the electronic and physical structure of their interfaces. Leaning on these fundamentals and practicalities, the material behavior and functionality of semiconductor-oxide heterostructures is discussed, and their potential as device building blocks is highlighted. The culmination of this discussion is a review of recent advances in the development of prototype devices based on semiconductor-oxide heterostructures, in areas ranging from silicon photonics to photocatalysis. This overview is intended to stimulate ideas for new concepts of functional devices and lay the groundwork for their realization.

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Section: Growth Physical and Electronic Structurementioning

confidence: 99%

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Kumah

Ngai

Kornblum

2019

Adv Funct Materials

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“…marked by a red circle) results from the lattice mismatch of 1 %. (14) Electrical characterization of LaLuO3…”

Section: Methodsmentioning

confidence: 99%

“…This result is sufficient for the use of hexagonal LLO in a microelectronic device. The high crystallinity of the layer is proven by a rocking curve around the (0002) reflection exhibiting a FWHM of 0.05° (14). A comparison of the -2θ-scan of the LLO (0002) reflection at the day of deposition and one and a half year later reveals no change of the crystal structure as shown infigure 2b.…”

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confidence: 86%

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(Invited) Ternary Rare Earth Based Oxides for Nitride Based Devices

et al. 2016

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Ternary rare earth oxides are promising candidates for future gate oxides. Therefore GdScO3 and LaLuO3 were investigated with regard to their suitability as gate dielectric. The layers were deposited by pulsed laser deposition and the crystal structure, stoichiometry, layer roughness and band gap were investigated. GdScO3 can be grown hexagonal and amorphous and LaLuO3 can be grown hexagonal, orthorhombic and amorphous. All investigated layers revealed smooth surfaces, exhibited band gaps higher than 5 eV and a permittivity higher than 20. These results show that GdScO3 and also LaLuO3 are promising candidates as a future gate dielectric based on nitride semiconductor devices.

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“…3(a), orange) originates from δ I(t) at the pinch-off of the nanowire induced by a single finger gate. It is converted to S pot ( f ) by the measured I(V Gate ) using α hBN = 0.12 ± 0.02 eV/V for the hBN device as determined from the corresponding QD CDs with error bars as deduced from CD variations and α LaLuO 3 = 0.55 ± 0.11 eV/V for the LaLuO 3 device deduced by scaling α hBN for the different thicknesses (hBN: 35 ± 2 nm, LaLuO 3 : 50 ± 5 nm) and for the different ε (hBN: 4 53 , LaLuO 3 : 26±1 54 ). Remarkably, S pot ( f ) of the h-BN device is more than two orders of magnitude lower than for the LaLuO 3 device (Fig.…”

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confidence: 99%

Exfoliated hexagonal BN as gate dielectric for InSb nanowire quantum dots with improved gate hysteresis and charge noise

Jekat,

Pestka,

Car

et al. 2020

Preprint

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We characterize InSb quantum dots induced by bottom finger gates within a nanowire that is grown via the vapor-liquidsolid process. The gates are separated from the nanowire by an exfoliated 35 nm thin hexagonal BN flake. We probe the Coulomb diamonds of the gate induced quantum dot exhibiting charging energies of ∼ 2.5 meV and orbital excitation energies up to 0.3 meV. The gate hysteresis for sweeps covering 5 Coulomb diamonds reveals an energy hysteresis of only 60 µeV between upwards and downwards sweeps. Charge noise is studied via long-term measurements at the slope of a Coulomb peak revealing potential fluctuations of ∼1 µeV/ √ Hz at 1 Hz. This makes h-BN the dielectric with the currently lowest gate hysteresis and lowest low-frequency potential fluctuations reported for low-gap III-V nanowires. The extracted values are similar to state-of-the art quantum dots within Si/SiGe and Si/SiO 2 systems.Recently, nanowires of indium antimonide (InSb) and indium arsenide (InAs) 1-4 came back into focus due to their large spin-orbit coupling 5-7 that in combination with magnetic fields and a relatively strong proximityinduced superconductivity 8-10 enables tuning of Majorana modes 11-14 as a basis for topologically protected quantum computing. [15][16][17] Typically, the nanowires are tuned electrically by a number of bottom finger gates that are separated from the nanowire by a gate dielectric. 12,18 It is well known that both charge noise and hysteresis of gateinduced potentials deteriorate the performance of semiconductor qubits, [19][20][21][22] as is also expected for the prospective Majorana qubits. 23,24 Hence, it is crucial to optimize the dielectric in terms of unintentional charge fluctuations.For exfoliated two-dimensional materials such as graphene, it turned out that hexagonal boron nitride (h-BN) is ideal for that purpose. 25,26 For example, it improves the charge carrier mobility by more than an order of magnitude compared to the previously used Si/SiO 2 . 27,28 Furthermore, it is easy to fabricate. Thus, exploiting exfoliated h-BN as gate dielectric for low-gap III-V nanowires is appealing. First experiments used h-BN to separate the global Si/SiO 2 back gate from an InSb nanowire enabling the first quantized conductance steps in such nanowires at zero magnetic field. 29 Subsequently, measurements on proximity-coupled InSb nanowires on h-BN showed magnetic field induced zero bias peaks, indicative of the presence of Majorana zero modes. 30,31 However, Coulomb diamonds (CDs) with excited states in a gate-induced quantum dot (QD) have not been reported and, more importantly, the charge noise and gate hysteresis of such nanowires on h-BN have not been studied. Reports on these properties are only available for other types of dielectrics.

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Hexagonal LaLuO3 as high-κ dielectric

Cited by 6 publications

References 18 publications

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

Epitaxial Oxides on Semiconductors: From Fundamentals to New Devices

(Invited) Ternary Rare Earth Based Oxides for Nitride Based Devices

Exfoliated hexagonal BN as gate dielectric for InSb nanowire quantum dots with improved gate hysteresis and charge noise

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